Having a fridge laser could spare you from food poisoning

New method promises to cheaply and easily detect wriggling bacteria on your grub.

While figuring out whether the leftovers in your fridge have gone bad or not, the sniff-test just doesn’t cut it. But unfortunately, there are virtually no consumer-based tests to assure you that your food hasn’t turned, which is a huge public health problem. Each year, around 50 million Americans get food poisoning, and around 3,000 die.

Now, a research group in South Korea has come up with a possible solution, which can be briefly summarized with: pew, pew, nom, nom.

That’s right, researchers at the Korea Advanced Institutes of Science and Technology have developed a fridge-mountable laser that detects the squirming movements of microbes on the surface of your chow. The method is cheap, easy to use, and requires no contact with the contaminated food, making it an ideal solution to a common health problem, the authors suggest.

The method works by zapping food with a series of laser shots while using a camera to watch how the light of each zap scatters off the surface. If the surface is still, the scatter pattern will stay completely or almost completely the same with repeated laser fire. But if the food is swarming with infectious bacteria, the scatter pattern will change in a matter of seconds. This is because microbes tend to propel themselves around with whip-like tails, called flagella, causing the light to scatter differently as they wriggle and swim to and fro.

As a proof-of-concept, the researchers tested their laser method on chicken breasts that were either clean or purposefully smeared with infectious bacteria, namely E. coli and B. cereus. The laser method could easily distinguish which chicken samples were contaminated and to what extent.

The authors suggest that such a laser-camera setup could be easily installed in fridges and commercial food processing plants.

Of course, the method has its limits. The laser scatter won’t pick up non-twitching contaminants, such as toxins and viruses, including norovirus. And it can't distinguish between types of moving microbes. But the researchers are still hopeful that it could substantially reduce food-borne illnesses.

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